Assessment of the parasitism potential of three parasitoids of fruit fly, Bactrocera spp. (Diptera: Tephritidae) under laboratory conditions

Muhammad Hamayoon Khan

doi:10.19045/bspab.2019.80099

Abstract

The parasitism potential of a pupal parasitoid, Dirhinus giffardii Silvestri and two larval-pupal parasitoids, Diachasmimorpha longicaudata (Ashmead) and Aganapis daci (Weld) was assessed against Bactrocera spp. under laboratory conditions. Three different types of hosts, viz. Bactrocera zonata (Saunders), Bactrocera dorsalis (Hendel) and Bactrocera cucurbitae (Coquillett) were reared on artificial larval diet and known number of pupae and larvae of each fruit fly species were offered to the respective parasitoids in glass cages in a no choice test. Results on the parasitism potential of D. giffardii towards pupae of different fruit fly species revealed that the highest per female parasitism was recorded on B. zonata (16.72 ±1.67). Adult emergence percentage of D. giffardii did not differ significantly among all the three Bactrocera spp. Sex ratio of the emerged parasitoids revealed maximum percent females (61.64 ± 2.67) from pupae of B. cucurbitae. Similarly per female parasitism by D. longicaudata was also significantly the highest on larvae of B. zonata (26.40 ± 1.79) with maximum adult emergence percentage of 93.41 ± 2.54. Sex ratio of the emerged D. longicaudata did not differ significantly. Parasitism rate of A. daci was significantly the highest on larvae of B. zonata (24.88 ± 2.01) with insignificant differences in the adult emergence percentage. Sex ratio of A. daci showed that percent females from the emerged parasitoids were the highest (54.2 ± 3.44) on B. dorsalis. Relative collective parasitism per female by all the three fruit fly parasitoids revealed that highest parasitism rate (23.7 ± 2.26) was exhibited by D. longicaudata followed by A. daci (22.72 ± 2.14). The study manifested that B. zonata could be the ideal host for laboratory rearing of these parasitoids. Keywords: Bactrocera; Emergence; Fruit fly; Host; Parasitoids; Parasitism; Sex ratio http://dx.doi.org/10.19045/bspab.2019.80099

Highlights

The parasitism potential of a pupal parasitoid, Dirhinus giffardii Silvestri and two larval-pupal parasitoids, Diachasmimorpha longicaudata (Ashmead) and Aganapis daci (Weld) was assessed against Bactrocera spp. under laboratory conditions
Relative collective parasitism per female by all the three fruit fly parasitoids revealed that highest parasitism rate (23.7 ± 2.26) was exhibited by D. longicaudata followed by A. daci (22.72 ± 2.14)
Results of the present studies manifested that the pupal parasitoid, D. giffardii exhibited higher rate of parasitism on pupae of B. zonata and B. dorsalis, which are almost of identical size, compared to B. cucurbitae

Summary

Introduction importance in the tropical and subtropical

About 50 species in this genus are considered to be highly destructive and major polyphagous pests of horticultural and vegetable crops [6-8] Among these the Bactocera cucurbitae (Coquillett), Bactocera dorsalis (Hendel) and Bactrocera zonata (Saunders) (Diptera: Tephritidae) inflict heavy losses to a wide range of fruits and vegetables in Pakistan. D. longicaudata is a larval-pupal parasitoid of several fruit fly species and is native to Southeast Asia [17, 18] It has been used in augmentative biological control programs against B. dorsalis [19]. Sex ratio of the emerged parasitoids revealed that the percent females of D. longicaudata from all the three species of Bactrocera did not differ significantly (Figure 2). Percent adult emergence of A. daci did not differ significantly among all the treatments, the highest (93.84 ± 3.14) was recorded on B. zonata and the lowest (91.59 ± 3.23) on B. cucurbitae (Table 3). Means followed by different letters in each column show significant differences (P < 0.05)

Discussion

Findings

Fopius arisanus